Heavy metal toxicity in earthworms and its environmental implications: A review

Abstract

Earthworms are important soil organisms, contributing to many beneficial ecological services that can be harmed by heavy metal contamination. Because of their permeable skin and constant contact with soil through their digestive tract, they are extremely sensitive to soil contamination. Heavy metals get bioaccumulated in their bodies and cause major health problems. In this review, we describe the findings of various studies on the toxicity of heavy metals to earthworms, mechanisms of toxicity, detoxification responses and consequences on the environment. Heavy metals have deleterious impact on earthworms at all levels of organization, including inhibiting enzyme activities, causing DNA damage, reducing survival, growth and cocoon production, altering behavior and reducing total earthworm community diversity and biomass. These negative effects of heavy metals on earthworms can have disproportionate adverse consequences for community stability as well as serious ecological consequences for the entire terrestrial ecosystem. So, heavy metal pollution of soil poses a serious threat to earthworms, reducing their activity and posing a risk to the environment and human health.

Keywords

• Earthworms
• Environment
• Heavy metals
• Toxicity
• Soil